1. Field of the Invention
The present invention relates to a method of implementing an endoscopic surgical procedure on a patient, and more particularly, is directed to a novel and unique technique of performing a uniportal palmar subligmentous endoscopic carpal tunnel release. Moreover, the invention is also directed to the provision of a unique endoscopic surgical instrument adapted to be employed in the implementation of the foregoing method of endoscopically effecting the carpal tunnel release.
Carpal tunnel syndrome is a numbness in the thumb, index, middle and ring fingers resulting from pressure being exerted on the median nerve inside the carpal tunnel, interfering with the function of such median nerve. This may readily manifest itself as a pain radiating as far as the shoulders and neck of the patient, resulting in impaired grasping ability by the hand and loss of sleep. This physical phenomenon is the result of repetitive work and motions being carried out with the hand over lengthy periods of time, and is experienced by more ever younger people.
In essence, the carpal tunnel is formed by an arch of the eight wrist bones, spanned on its palmar surface by the transverse carpal ligament, the flexor retinaculum. The carpal tunnel functions as a large mechanical pulley to provide the appropriate moment arms for the digital flexor tendons as they pass through the tunnel. The tendons can then transmit force out into the fingers and impart only an appropriate amount of tension to develop torque at the level of the wrist.
Within the carpal tunnel, these tendons are lubricated and nourished by two synovial membranes--the radial and the ulnar bursa. The median nerve also shares the carpal tunnel, then branches out to provide sensory innervation to the palmar surfaces of the thumb, index, long and a portion of the ring finger. In addition, a small motor branch of the median nerve supplies the thenar muscles, which are responsible for lifting the thumb into opposition with the fingers.
Currently, a considerable array of methods or surgical techniques, and suitable therewith correlated surgical instruments, are being employed for purposes of implementing surgical procedures in effectuating carpal tunnel release in patients, and are generally designed for particular and highly specialized applications in this medical technology.
The customary procedure in implementing carpal tunnel release has heretofore been the forming of a lengthy incision, up to 8 cm in length across the palm from the wrist to the middle thereof, resulting in an unsightly scar, requiring division of all anatomical structures between the skin and the flexor retinaculum; i.e. the transverse carpal ligament. This created the potential for inadvertently cutting or injuring the palmar cutaneous nerve. Moreover, the patient normally encountered significant postoperative pain and discomfort, weakness of grip and pinch strength because of pillar infraction and the excessively lengthy extent of the incision. Such open surgery not only normally left the patient with a cosmetically unsightly scar extending from the wrist to the center of the palm, as mentioned hereinbefore, but also necessitated a lengthy and painful convalescence for the patient, whereby this convalescent period frequently caused the hand to be incapable of any significant physical work or manipulation for many weeks and even months, thereby effectively rendering the patient incapable of carrying out any meaningful work with the operated on hand and resulting in considerable financial losses being sustained by the patient.
Among more recent developments and advances in such surgical procedures, arthroscopic surgery employing the use of endoscopic devices has found widespread application, among others in connection with carpal tunnel release, in that in comparison with earlier customary surgical methods, any incisions necessary for such endoscopic/arthroscopic surgical procedures have been considerably reduced in size, thereby alleviating potential postoperative complications and pain encountered by the patient, while reducing any scarring to cosmetically desirable levels. Among various types of surgical procedures, techniques involving approaches by means of arthroscopic and endoscopic systems to carpal tunnel surgery have been acknowledged as being superior in providing significant advances over earlier so-called open surgical procedures necessitating large incisions. Such endoscopic surgical procedures have found widespread acceptance in effectuating carpal tunnel release for the purpose of alleviating the symptoms in a patient caused by carpal tunnel syndrome, also referred to as tardy median nerve palsy, normally caused by the compression of the median nerve within the carpal tunnel.
These more recent endoscopic surgical approaches to remedying varying types of surgical problems afforded desirable alternatives to such earlier open surgical procedures, and especially when applied to effectuating carpal tunnel release, have found widespread favor with surgeons and patients in comparison with the earlier surgical methods which primarily constituted complex open surgical procedures, and which involved lengthy and painful postoperative convalescent periods.
2. Discussion of the Prior Art
Among numerous publications which describe recent advances in endoscopic surgical methods and instruments employed in connection therewith, particularly such as may be employable for carpal tunnel release procedures, there may be found the Agee carpal tunnel release system as disclosed in Agee, et al. U.S. Pat. Nos. 4,963,147 and 5,089,000, both of which disclose endoscopic surgical instruments and surgical procedures implemented therewith, which when applied to carpal tunnel release through an effective severing of the flexor retinaculum, or transverse carpal ligament, are adapted to provide relief to the patient. However, the instrument and methods developed by Agee, et al. as described in those publications, although superior to open surgery, inhibit readily unobstructed visualization of the surgical site during the sequence of severing the flexor retinaculum and do not provide adequate control in the manipulation of the instrument so as to reduce the inherent danger of damage to surrounding nerves and tissue to an acceptable minimum, and additionally necessitate the forming of two entry portals or incisions in the wrist and hand. Moreover, the endoscopic instruments developed in Agee, et al. are relatively cumbersome and expensive, requiring the surgeon to always use both of his hands, and necessitate the use of a swivel cutting blade construction operable independently of a viewing scope, which does not always provide the appropriate visualization during cutting of the flexor retinaculum so as to potentially present the danger of causing damage to adjacent or contiguously located tissue or nerves relative to the operating site, which could lead to serious and possibly permanent injury to the patient.
Another surgical system and instrument providing for an advanced technique over Agee, et al., which is particularly adapted for carpal tunnel release through the intermediary of an endoscopic surgical procedure is disclosed in Chow U.S. Pat. No. 5,029,573. However, in that instance, although setting forth a considerable advance over the methodology disclosed in the Agee, et al. U.S. patents, the surgical procedure employed by Chow requires the formation of two entry and exit portals or incisions, one in the wrist area and one in the palm, and the passage of an endoscopic medical instrument, such as an obturator through a considerable length beneath the subcutaneous areas of the palm of the patient. Again, the necessity for two widely separated incisions or entry portals, and the requirement for inserting a scope from one end of the instrument from one portal and with the instrument extending outwardly from the other portal or incision, while surgically severing or cutting through the flexor retinaculum or transverse carpal ligament from the other portal or incision, engenders a considerable obstruction toward a clear nonproblematic visualization of the operating sate during the severing of the transverse carpal ligament and, once again, raises the specter of a potential risk of causing injury to tissue and nerves adjacent the operating site, especially such as to the median nerve, which could lead to serious permanent injury to a patient and possibly require additional corrective surgery necessitating subjecting the entire surgical or operating site to open surgery. Moreover, Agee, et al. and Chow require the surgeon to simultaneously employ both hands during the surgical procedures, thus necessitating the utilization of an unusually high degree of dexterity in manipulating the various components of the endoscopic surgical instruments.